Grinding machine



July 2l, 1959 y Q. E. HILL v 2,895,265

l GRINDING MACHINE Filed Dec. 5, 1956 3 Sheets-Sheet 1 ATTORNEY July 21,1959 o. E. HILL GRINDING MACHINE` Filed Dec. 5, 1956 3 Sheets-Sheet 2INVENTOR O/VA E. H/Ll.

LA JM'L H TTORNEY July 21, 1959 v o. E. HILL. 2,895,265

` GRINDING MACHINE Filed Dem.` 5, 1956 v :s sheets-sheet :s

| NToR ONA E. H/YLL A TTOENEY United States Patent GRINDING MACHINE OivaE. I-Iill, Worcester, Mass., assignor to Norton Company, Worcester,Mass., a corporation of Massachusetts Application DecemberjS, '1956,Serial No. 626,484

8 Claims. (Cl. l51-165) The invention relates to grinding machines andmore particularly to a wheel feeding and wheel truing apparatus.

One object of the invention is to provide a simple and thoroughlypractical grinding machine feeding and truing apparatus. Another objectis to provide a truing apparatus which may be operated eitherintermittently or continuously. VAnother object is to provide a truingtool feeding mechanism by which the truing tool may be fed at each endof a reciprocatory stroke either at a fine feed for continuous truing orat a coarser feed for intermittent truing.

Another object of the invention is to provide a manually operable clutchmechanism whereby either a fine feed for continuous truing, or a coarserfeed for an intermittent feed may be obtained at each end of thetraversing stroke of the truing tool.

A further object of the invention is to provide a grinding wheel feedcompensating mechanism which is arranged to impart a fine compensatingadjustment after each complete reciprocation of the truing tool, or acoarser compensating adjustment after each reciprocation of the truingtool when set up for intermittent truing to compensate for wheel wearand truing. Other objects will be in part obvious or in part pointed outhereinafter.

In the accompanying drawings, in which is shown one of various possibleembodiments of the mechanical features of this invention:

Fig. 1 is a fragmentary sectional view through a grinding machineshowing the wheel feeding mechanism;

Fig. 2 is a vertical sectional view, on an enlarged scale, takenapproximately on the line 2-2 of Fig. 1, showing the wheel feedcompensating mechanism;

Fig. 3 is a vertical view, taken approximately on the line 3-3 of Fig.2, through the feed compensating mechanism;

Fig. 4 is a vertical sectional view, taken approximately on the line 4-4of Fig. 2, through `the feed compensating mechanism; f

Fig. 5 is a vertical sectional View through the grinding wheel truingapparatus;

Fig. 6 is a fragmentary plan view of the truing apparatus as shown inFig. 5 having parts broken away and shown in sections; and

Fig. 7 is a combined hydraulic and electric diagram of the actuatingmechanisms and the controls therefor.

A cylindrical grinding machine has been illustrated in the drawingscomprising a base 10 which supports a transversely movable wheel slide11 on the usual ways formed on the upper surface of the base 10. Thewheel slide 11 supports a rotatable wheel spindle 12 in the usualspindle bearings (not shown). A grinding wheel 13 is mounted on one endof the spindle 12.

A driving mechanism is provided for imparting a rotary motion to thewheel spindle 12 and the grinding wheel 13 comprises an electric motor14 mounted on the upper surface of the wheel slide 11. The motor isprovided with a motor shaft 15 having a multiple V-groove pulley 16 ICCwhich is connected by multiple V-belts 17 with a multiple V-groovepulley 18 mounted on the other end of the wheel spindle 12.

A wheel feeding mechanism is provided comprising a rotatable feed screw20, the right hand end of which is journalled in anti-friction bearings21 carried by a slidably mounted sleeve 22 which is supported in acylindrical aperture 23 formed inthe base 10. The left hand end of thefeed screw 20 is slidably keyed within a rotatable sleeve 24 which isjournalled in an anti-friction bearing 25.

supported by the base 10. The wheel slide 11 is provided with adepending half-nut 26 which meshes with or engages the feed screw 20.

A manually operable feeding mechanism is provided for the feed screw 20comprising a manually operable feed wheel 27 which is rotatablysupported on a shaft 28. The feed wheel 27 is connected by a well knownmicrometer feed adjusting mechanism 29 with a pinion 30 which mesheswith a gear 31 rotatably supported on the shaft 2S. A gear 32 is iixedlymounted to the gear 31 and meshes with a gear 33 which is keyed onto theleft hand end of a rotatable shaft 34. The left hand end of the shaft 34is journalled in an anti-friction bearing 35. The right hand end of theshaft 34 is rotatably supported within a hollow shaft 36 which isslidably keyed within the sleeve 24. A wheel feed compensatingmechanism, to be hereinafter described is connected between the shaft 34and the hollow shaft 36 to impart a rotary motion to the feed screw 20when the feed wheel 27 is rotated.

A hydraulically operated mechanism is provided for imparting a rotarymotion to the feed screw 20. This mechanism has not been illustrated indetail in the present application since it is substantially identicalwith that shown in the prior U.S. Patent No. 2,572,529 to H. A. Silvendated October 23, 1951. This mechanism comprises a cylinder 40 whichcontains a slidably mounted piston 41. The upper surface of the piston41 is provided with rack teeth 42 which mesh with a gear 43 which isrotatably journalled in spaced' anti-friction bearings 44 and 45. Ashaft 46 is rotatablyjournalled within the gear 43 and is provided witha gear 47 ixedly mounted on the right hand end thereof (Fig. 1). Aclutch mechanism is provided for connecting the gear 43 to the shaft 46.This clutch mechanism comprises an internal gear-shaped clutch element48 which as shown in Fig. l meshes with an external gear-shaped clutchelement 49. An actuating knob 50 is mounted on the left hand end of theshaft 46. When it is desired to declutch the shaft 46 and the gear 47from the gear 43, the knob 50 is moved toward the right to shift theshaft 46 toward the right so as to slide the internal gear-shaped clutchelement 48 out of mesh with the gear-shaped clutch element 49.

The gear 47 meshes with a gear 55 which is keyed to the shaft 34. A gear56 is fixedly mounted relative to the gear 55 and meshes with a pinion57 formed on the left hand end of a shaft 58. The shaft 58 is supportedwithin a casing S9 which supports the feed compensating mechanism. Thecasing 59 supports a shaft 60 which is provided with a gear 61 on itsright hand end. The gear,

61 meshes with a gear 62 which is fixedly mounted on the hollow shaft36. The shafts 58 and 60 are normally held against rotation relative tothe casing 59 in a manner to be hereinafter described. It will bereadily apparent that a rotary motion imparted to the gear 55, either bythe manually operable feed wheel 27 or the piston 42 will be impartedthrough the gear 5S to rotate the gear 56. Due to the fact that theshafts 59 and 60 are normally held against rotary motion, a rotarymotion of the gear 56 will be transmitted through the pinion 57 torotate the casing 59. Rotary motion of the casing 59v feed screw 20. Thedirection of rotation of the feed wheel 27 or the direction of themovement of the piston 41 serves to determine whether a forward orrearward movement of the wheel` slide 11 is obtained.

A wheel feed vcompensating mechanism is provided which operates and inVtimed relation with a grinding wheel truing apparatus to be hereinafterdescribed. 'T he truing apparatus is arranged so that either anintermittent or a continuous truing operation may be obtained. A duplexwheel feed compensating mechanism is provided so that wheel compensationmay be made either during an intermittent truing operation of the wheelor during a continuous truing operation on the grinding wheel.

The compensation of the wheel feed mechanism for continuous truing ofthe grinding Wheel will now be described. A hydraulically operated feedcompensating unit 64 is supported on the shaft `and isvprovite with acylinder '65 (Fig. 7.) which contains a slidably mounted piston 6.6. Thepiston 66 carries a spring pressed pawl'67 which is arranged to engagethe teeth of a ratchet wheel V68. 'The ratchet wheel 68 is mounted onthe `left hand endof a rotatable shaft 69 which also supports a worm 70meshing with a worm gear 71 (Figs. 2 and 3) keyed onto the shaft 58. Acompression spring 72 (Figs. 3 and 7) serves normally -to hold thepiston 66 in a downward position. 'When it is desired to cause acompensating adjustment of the wheel feed during con tinuous truing, uidunder pressure is passed from valve chamber 109 and through the pipesY76 and 78 into a cylinder chamber 73 to cause an upward movement of thepiston 66. During the upward movement of the piston 66 the pawl 67 ridesidly over the teeth of the ratchet wheel 68 (Figs. 3 and7). The upwardmovement of the piston 66 `continues until a piston rod 74 attached tothe upper end of the piston 66 lengages an adjustable stop screw 75. Thepiston 66 remains in this position until the piston 128 and truing tool138 start traversing toward the left. When fluid underpressure isallowed to exhaust from the cylinder chamber 73, the releasedcompression of the spring 72 causes a downlward movement of the piston66 during which movement the pawl 67 turns the ratchet wheel A68 toimpart a compensating adjustment to the feed screw 20 as the truing tool138 starts its traversing stroketoward the left. The operativeconnections between the continuous compensating adjusting mechanism andthe feed screw 20 are such that foreach tooth on the ratchet wheel, acompensating adjustment will be imparted to the feed screw toadvance'the wheel slide 11\.00001 of an inch. The number of teeth theratchet wheel 68 is indexed during each compensating adjustment may bedetermined by the upward movement of the piston 66 as governed by thestop screw 75.

A compensating adjustment by the mechanism above described during acontinuous grindingwheel truing operation is obtained in the followingmanner. Rotary motion of the worm gear 71 imparts'a rotary motion to thepinion 57 to cause the pinion 57 to roll upon the gear 56 therebyirnpartinga slight rotary motion tothe casing 59 (Fig. l). The rotarymotion of the Vcasing 59 is transmitted through thenow stationary gear61 `to impart a rotary motion Vto the gear 62 and thereby to impart acompensating adjustment to the feed screw 20. When fluid under pressureis passedthrough apipe 76, Vthrough a control valve 77 andthrougha pipe78 into the cylinder chamber 73, the continuous truing compensator isactuated, as above described.

The wheel feeding compensating mechanism for compensating during anintermittent grinding wheel truing operation will now be described. Thefeed compensating unitf64 is provided with a cylinder 85 which containsa slidably mounted piston v86. The piston 86 carries a springpressedpawl 87 which is arranged to engage the teeth of a ratchet wheel 88. Theratchet Wheel 88 is mounted on the right hand end of a rotatable shaft89 (Fig. 2) which `also supports a yworm 90 meshing With a worm gear 91keyed onto theshaft 60 (Fig. 2). A compression spring 92 (Figs. 4 and 7)serves normally to hold the piston 86 in an upward position. When it isdesired to cause a compensating adjustment of the 'wheel feedingmechanism during an intermittent grinding wheel truing operation, duidunder vpressure is passed to a cylinder chamber 93 to causeadownwardmovement of the piston 86. During the downward movement of the piston86'the pawl 87 engaging the teeth of ktheratchet wheel 88 imparts acounter-clockwise rotary movement to the ratchet ywheel 88 andtheVshaft'89. The worm and the gearing associated with the compensatingmechanism are such 'that `for each tooth on the ratchet wheel 85, a feedcompensating adjustment of .0005 of an inch adjustment is made. Thedownward movement of the piston 86 continues until arod 94 attached tothe lower end'o'f the piston 86 engagesan adjustable stop-screw 95.When'iluid is'allowed to exhaust'from the cylinder charnber 93 thereleased compression of the spring 92 causes an upwardmovement ofthepiston '86 during which'movementthepawl '87 rides idly overthe teeth 'oftheratchet wheel 88. The 'number of teeth ofthe ratchet wheel 88 whichare lpicked up at each actuation of the cornpensating mechanism isdetermined bythefadjustment of the stop screw 95.

A compensating adjustment by'thernechanism above described Vduring anintermittent grinding wheel truing operation is obtained in thefollowing manner. Rotary motion of the worm gear 91 serves to impart `arotary motion to the-shaft`60 and the gear "61 to impart a correspondingrotary motion to the Agear 62 and lthe 'feed screw 20. During thiscompensation, -norotary motion is imparted to the casing 59 relative tothefsha'ft-34.

When fluid under pressure'is lpassed `through a pipe 96, through acontrol valve\97 Aand through a pire. 98 into the cylinder chamber93,-a'cornpensating feed adjustment is made when the truing tool 13S starts,traversing towardthe left acrossthe operative 'faoeofthegr'inding wheelduring an intcrmittent'truing operation.

Only one of the feed compensators is operative at a given time. If thetruing apparatus AAto'he vhereinafter described is set for automaticcontinuous truing of the grinding wheel'the valve-'97isrnfanually'closed tovrender cylinder 85 and the associated partsoftheintermittent comprisingfmechanism inoperative. Similarly/if the truingapparatus is set for an intermittent truing operation, the valve 77 isclosed and the valve '97 opened thereby rendering the cylinder- 65andthe associated parts'of the continuous compensating vmechanism Varerendered inoperative. The feed compensation ltakes place when the truingtool 138 starts traversing toward the left regardlesswof whether thetruing apparatus is set for intermittent or `continuous truing.

The grinding'wheel-feed mechanism during normal op eration of thegrinding machine regardless of whether it is manually or hydraulicallyoperated is `unwound and wound in a manner substantially the vsame rasvthat disclosedin the above mentioned ULS. 'Patent'No 2,572,529, thatis, after a grinding Voperation hasbeen completed and before thegrinding starts on the next workpiece. This unwinding and winding of thewheelfeedingmechanism, not only takes up any backlash in-the feedmechanism parts but also finds the compensationincrement orincrements ina manner `similar'to -that to fhe hereinafterdescribed in connection`with the grinding -wheel truing apparatus.

A fluid pressure system is provided for supplying fluid under pressureto the various mechanisms of the machine. This system may comprise amotor driven fluid pump A105) which may be started by closing a manuallyoperable switch 99. The pump 100 draws fluid through a pipe 101 froma'reservoir 162 and forces iluid under pressure through a pipe 103. Arelief Valve 104is 'connected in 'S the pipe line 103 to facilitate bypassing excess uid under pressure directly from the pipe 103 into thereservoir 102 so as to maintain a substantially uniform operatingpressure the iluid system.

A control valve 105 is provided comprising a valve stem 106 having aplurality of spaced valve pistons forming a plurality of spaced valvechambers 107, 108, and 109. The slidably mounted valve member isprovided with a central passage 110 which interconnects the valvechamber 107 with the valve chamber 109. A compression spring 111 servesnormally to hold the valve stem 106 in a left hand end position, asshown in Fig. 7. A solenoid S1 is provided which when energized servesto shift the valve stem into a rearward end position. A pipe 112exhausts Huid from the control valve 105 through a throttle valve 113and through a pipe 114 into the reservoir 102. The control valve 105serves in a manner to be hereinafter described to control the admissionto an exhaust of fluid from the feed compensating mechanisms abovedescribed and also to a grinding wheel truing mechanism to behereinafter described.A

The grinding wheel 13 is partially surrounded by a wheel guard 120 whichis fastened to or iixedly mounted on the wheel slide 11. The wheel guard120 is provided with an upwardly extending housing 121 which serves as asupport for a grinding wheel truing apparatus 122. The truing apparatus122 is similar to that disclosed in my prior U.S. Patent No. 2,647,504dated August 4, 1953. The truing apparatus is provided with alongitudinally movable slide 123 (Fig. 5) which is supported byantifriction slide-ways 124 and 125 carried by a truing apparatus base126. A hydraulically operated mechanism is provided for traversing theslide 123 longitudinally. This mechanism comprises a cylinder 127 whichcontains a slidably mounted piston 128 (Fig. 7 The piston 128 isconnected to the right hand end of a piston rod 129, the left hand endof which is fixedly mounted to the slide 123. It will be readilyapparent from the foregoing disclosure that when fluid under pressure ispassed through the pipe 76 into a cylinder chamber 130 at the left handend of the cylinder 127, the piston 128 together with the slide 123 willbe traversed toward the right. During this movement fluid Within acylinder chamber 131 exhausts through the pipe 96. Similarly when fluidunder pressure is passed through the pipe 96, the piston 128 togetherwith the slide 123 will be moved or traversed toward the left (Fig. 7).

The longitudinally movable slide 123 supports a vertically arrangedsleeve 135. A vertically arranged truing tool holder shaft 136 issupported within the sleeve 135. A truing tool holder 137 having adiamond or truing tool 138 is mounted at the lower end of the shaft 136.The sleeve 135 is arranged to slide vertically within the slide 123. Afollower 139 is fastened to the sleeve 135 and rides upon a forming bar140 which is iixedly mounted on the truing apparatus base 126. In thepresent case the forming bar 140 is provided with a plane face so thatthe truing tool will be moved in a straight line path when thelongitudinally movable slide 123 is traversed.

A suitable feeding mechanism is provided for adjusting the truing tool138 vertically relative to the sleeve 135 and the slide 123. Thismechanism comprises a feed screw 141 formed on the upper end of thetruing tool holder shaft 136. A rotatable feed nut 142 meshes with thefeed screw 140. A gear 143 is` keyed to the feed ntut 142 and mesheswith a small gear 144 which is keyed on a rotatable shaft 145. The upperend of the shaft 145 is provided with a manually operable feed wheel 146by means of which the nut 142 may be rotated in either directionvertically to adjust the position of the truing tool 138.

The grinding wheel truing apparatus is preferably arranged so thateither a manually controlled intermittent or a continuous grinding wheeltruing cycle may be ob- -tained. A truing tool feeding mechanism isprovided 5 which is actuated at the ends of the reciprocating stroke ofthe truing tool 138. The feed nut 142 is rst unwound or backed-olf atwhich time the feed nut 142 is then given a predetermined incrementalrotary motion to feed the truing tooldownwardly by a'. predeterminedincrement after which the feed nut is wound or advanced to apredetermined stopped position before the truing tool 138 starts itstraverse across the periphery face of the grinding wheel 13. The windingand unwinding of the feed nut before and after the incremental feedingmovement serves to take up backlash in the feed mechanism parts.

An oscillatable plate 150 (Figs. 5 and 6) is rotatably supported on thehub 151 formed integral with the gear 143. The plate 150 serves as asupport for the rotatable shaft and also for the truing tool feedingmechanism to be hereinafter described. The plate is normally held in theposition shown in Figure 6 with the stop surface 152 in engagement withan adjustable stop screw 153 by means of a compression spring 154. Thespring 154 is interposed between a bracket 155 which is fixed relativeto the truing apparatus slide 123 and a lug 156 depending from the plate150.

When the slide 123 moves longitudinally toward the right (Fig. 6), arearwardly projecting arm 157 formed integral with the plate 150 engagesa stud 15S carried by an adjustable dog 159 which serves to rock theplate 150 in a counter-clockwise direction. This movement of the plate150 serves to move the, now held stationary, gear 144 to impart acounter-clockwise rotary motion to the -gear 143 (Fig. 6) and the truingtool feed nut 142 to impart counterclockwise unwind movement to the feednut 142 in a manner to be hereinafter described. As soon as the slide123 starts moving toward the left, the released compression of thespring 154 rocks the plate 150 in a clockwise direction until the stopsurface 152 engages the stop screw 153 thereby imparting a rotary motionto the feed nut 142 to position the truing tool 138 for a traversingmovement toward the left across the operative face of the grinding wheel13.

Similarly, as the slide 123 approaches `the end of its traverse towardthe left, a cam 162 on the plate 150 engages a stud on an adjustable dog161. Continued movement of the slide 123 toward the left serves to rockthe plate 150 in -a counter-clockwise direction to unwind the feed nut142 at which time a rotary feeding increment is imparted to the nut 142.The nut 142 remains in this position until the slide 123 starts atraversing movement toward the right at which time the releasedcompression of the spring 154 rocks the plate 150 in a clockwisedirection until lthe stop surface 152 engages the stop screw 153 therebyimparting a wind motion to the feed nut 142 so as to position the truingtool 138 for a pass toward the right across lthe operative face of thegrinding wheel 13. It will be readily apparent from the foregoing thateach time the slide 123 approaches either end of lits longitudinaltraversing movement, the feed nut 142 is backed-off or unwound, afeeding increment is imparted to the feed nut 142 and as soon as theslide starts moving in the opposite direction, a rotary motion wind isimparted to the feed nut 142 thereby taking up backlash lin the feedmechanism parts and at the same time imparting a feeding increment tothe truing tool 138.

A truing tool feed unit 165 (Figs. 5, 6 and 7) is provided which isxedly mounted on the underside of the plate 150. The unit 165 togetherwith the plate 150 serves rotatably to support the shaft 145. A ratchetwheel 166 and a worm gear 167 are rotatably supported on the shaft 145and arranged so that one or the other may be clutched to the shaft 145,as desired. The shaft 145 is arranged for an axial movement relative tothe unit 165 so that a drive pin 168 (Fig. 5) fixedly mounted on theshaft 145 may be engaged with a notch in the hub .-of Ythe ratchet wheel166 (Figs. Sand 7) to lock .the ratchet wheel to ,the shaft 145. Or the.shaft 145 may be moved upwardly so that the drive pin ,168 engages anotch formed/in vthe downwardly projecting hub ofthe-worm gear 167. Aspring-pressed detent 169 (Fig. is arranged to engage one of `apluralityof .grooves formed inthe-periphery of the shaft 145so asyto facilitateholding the shaft to engage either the ratchet wheel l166 .or lthe worm-gear '167 relative thereto. If'the shaft -145 is moved vertically Ysothat the detent 169 engages acentral groove, the drive pin 168 is in aneutral ,position in which position both the ratchet wheel 166 yand the-worm gear 167 are declutched :from the shaft 145. If a ver-.y finefeeding increment is desired, the shaft 145 is moved upwardly so thatthe detent 169 -`engages the lower groove of the shaft 145 .togposition'the .drive pin 168 in van uppermost position so as to lock the worm.gear 167 relative to the shaft 145.

A uidrpressure operative mechanism iis provided `for actuating theratchet wheel -166 which -is ,arranged so that a feeding down movementof the truing tool 138 may be obtained `automatically at the ends of thetraversing stroke of the truing tool. This mechanism comprises acylinder -175 (Fig. 7) which contains a slidably mounted piston 176. Thepiston 176 is provided with a ,spring actuated pawl 177 which isarranged to engage the teeth of the ratchet wheel 166. A compressionspring 173 serves normally to hold the piston 176 .in an uppermostposition. The v piston 176 is provided with a downwardly extendingprojection 179 which is arranged to engagea stop screw 180 to determinethe stroke of the piston 176 and thereby to determine the number ofteeth of the ratchet wheel 166 which are Vpicked'at `each reciprocation.of the `piston 176. When uid under pressure is passed .through a pipe181 into a cylinder chamber 182, the piston 176 is moved downwardly sothat the pawl .177 .rides idly over the teeth of the ratchet `wheel 166.When fluid is exhausted from the pipe 181 from the cylinderchamber 182,the released compression .of the spring 178 causes `an upward movementof the piston 176 during which movement the pawl 177 engages the teethof the ratchet wheel 166 and turns it one or more .teeth in a clockwisedirection (Fig. 7). The number of teeth picked is determined by thesetting of the Ystop screw 180. The mechanism above described serves toinitiate a down feeding movement of the truing tool 138 as it :starts a.traversing movement toward the right.

.A similar mechanism is provided for imparting a downward feedingmovement to the truing `tool 138 as it starts a traversing movementtoward the left. This mechanism comprises a cylinder 185 which containsa slidably mounted piston 186. The piston 186 is provided with a springpressed pawl 187 which is arranged to engage the teeth of the ratchetwheel 166. A compression spring 188 serves normally to hold the piston1'86 in an uppermost position. The piston 186 is provided with adownwardly extending projection 189 which is arranged to engage anadjustable stop screw 190. 'The setting of the adjusting screw 190serves to determine the number of teeth of the ratchet wheel 166 .pickedby the pawl 187 during each actuation lof the piston 186. When fluidunder pressure is passed through the pipe '191 into a cylinder chamber192, the piston 186 is moved downwardly during which .movement the pawl187 engages the teeth of the ratchet wheel 166 and imparts a clockwiserotary motion to the ratchet wheel166.

Ashuttle type valve 195 is provided which is actuated by -and in `timedrelation with the movement of the piston 128. The valve 195 comprises aslidably mounted `valve member having a plurality -of valve pistonsformed toward the right, .uid under pressure passes through a passage199 into the valve chamber 197 and through the pipe 181 into thecylinder chamber 182 to impart an idle movement to the pawl 177. At thesame time uid under pressure passing through the passage 199 enters anend chamber 200 .and moves the slidably mounted valve member toward theright. When the valve member movesa suicient distance toward the rightto iirst cover and then uncover the port to the end of the pipe 201,fluid under pressure is cut off from the valve chamber 197 and the valvechamber 197 is opened to exhaust fluid from the cylinder chamber 182,through the pipe 181, through the valve chamber 197 and through a pipe201 into vthe reservoir 102. The movement of the slidably mounted valvemember 196 requires less fluid under pressure than that required to movethe piston 128, consequently the valve member 196 moves rapidly towardthe right so that a momentary shot .of fluid causes a downward movement.of the piston 176 to cause the pawl .17,7 to ride idly over the teethof the ratchet wheel 166 after which the released compression of thespring 178 causes an upwardmovement of the piston 176 and the pawl 177to impart an indexing movement to the ratchet wheel 166 therebyimparting a rotary motion to the shaft (Fig. 5) to rotate the small gear144, the large gear 143 and the feed nut 142 to impart a downwardfeeding movement to the truing tool 138.

During the movement of the valve member 196 toward the right fluidwithin an end chamber '202 exhausts through a passage 203 vinto thecylinder chamber 131 and through the pipe 96.

When the slide 123 together with the -piston 128 and the truing tool 138are at the right hand .end of the traversing movement, when uid underpressure is reversed and passed through the pipe 96 into thecylinderchamber 131, fluid `passes through the passage 203, through the valvechamber 198, through the pipe 191 into the cylinder chamber 192 to causedownward feeding movement of the pawl 187 which imparts a rotary motionto the ratchet wheel 166 and through the mechanism previously describedto impart a down feeding movement to the truing tool 138. As previouslydescribed the passage of fluid under pressure into the cylinder chamber131 passes through the passage 203 into the valve chamber 198 and at thesame time passes into the valve chamber 202 rapidly to move the valvemember v196 toward the left. During movement of the valve member 196toward the left a momentary shot of fluid under pressure passes throughthe pipe 191 to cause the downward movement of the piston 186 to indexthe ratchet wheel 166 after which the released compression of the spring188 causes an upward movement of the piston 186 so that fluid within thecylinder chamber 192 exhausts through the pipe 191, through the valvechamber 198 and through the vpipe 201 linto the reservoir 102. Thisfeeding mechanism above described serves to impart a controlled downfeeding movement of the truing tool at each end of the traversing strokeof the truing tool during an intermittent truing operation which may bemanually initiated in Va .manner to be hereinafter described.

The grinding wheel truing apparatus is arranged so that a continuoustruing of the grinding wheel may be obtained when desired. In this casea continuous reciprocation of the truing tool is provided with a finedown feeding movement of the truing tool at the end of each stroke ofthe truing tool slide. The worm gear 167 meshes with a worm 210 which ismounted on a rotatable shaft 211 (Fig. 6). A pair of spaced ratchetwheels 212 and 213 are mounted adjacent to opposite ends of the shaft211. In actual construction as shown in Fig. 5 the ratchet wheels 212and 213 together with the shaft 211 :are arranged at right angles to theratchet wheel 166 and the shaft 145. As shown diagrammatically in Fig. 7

Athe shaft 211 together with the ratchet wheels 212 and .through anormally closed limit switch LS1.

213 .are shown in the same plane wheel166. y Y

A spring actuated pawl 214'is carried by the piston 176 and a springpressed pawl 215 is mountedon the piston 186. When it is desired toobtain a ne feed during continuous truing operation, the knob 146together with the shaft 145 are moved upwardly so that the detent 169engages the lower groove on the shaft 145 and so that the driving pin168 engages the notch in the hub of the worm gear 167. In thisfpositionof the parts when lluid under pressure is admitted to the cylinderchamber 130 to cause the piston 128 together with the slide 123 to movetoward the right, fluid under pressure is passed through the passage 199and momentarily through the valve chamber 197 through the pipe 181 intothe cylinder chamber 182 to cause a downward movement'of the piston 176and the pawl 214. The pawl 214 engaging the ratchet wheel 212 imparts arotary motion to the shaft 211 and through the worm 210 and worm gear167 to impart a downward feeding movement to the truing tool 138. Thevalve member 196 moves rapidly toward the right so that uid from thecylinder chamber 182 may exhaust through the valve chamber 197 andthrough the pipe 201 into the reservoir 102 under the influence of thereleased compression of the spring 178 thereby returning the piston 176together with the pawl 214 to their initial positions as illustrated inFig. 7.

Similarly when fluid under pressure is admitted to the `cylinder chamber131 to start movement of the piston 128 together with the slide 123toward the left, fluid passes through the passage 203 into the valvechamber 198 and through the pipe 191 into the cylinder chamber 192 tocause a downward movement of the piston 186 together with the pawl 215thereby imparting a rotary motion to the ratchet wheel 213 which causesa fine downward feeding of the truing tool 138. The valve member 196moves rapidly toward the left so that pressure passes only momentarilythrough the valve charnber 198 and the pipe 191. When the valve member196 reaches the left hand end position, as shown in Fig. 7, the releasedcompression of the spring 188 causes an upward movement of the pawl 215and the piston 186 so that fluid within Ithe cylinder chamber 192exhausts through the pipe 191 through the valve chamber 198 and throughthe exhaust pipe 201 into the reservoir 102 thereby returning the pawl215 and piston 186 to an uppermost position.

As shown diagrammatically in Fig. 7, lthe ratchet wheels 212 and 213 andassociated parts are illustrated at right angles to their normalposition so as to clarify the operation of the mechanism. The ratchetwheel 2121 is shown as swung 90 to the left whereas the ratchet wheel213 is shown as swung at 90 toward the right so that actuation of eitheror both of the ratchet wheels imparts a rotary motion to the shaft 211in the same direction. Y

A manually operable knob 220 is mounted on the shaft 211 to facilitatemanual rotation of the shaft 211 to facilitate setting up the truingapparatus and positioning of the truing tool 138.

The operation of the improved grinding wheel truing apparatus will bereadily apparent from the foregoing disclosure. With the partspositioned as shown in Fig. 5, the apparatus is set for an intermittenttruing operation since the driving pin 168 is in engagement with thenotch in the hub of ratchet wheel 166. The switch 99 is manually closedto start the driving motor for the fluid pump 100. A manually operableswitch 216 is closed to start the -wheel driving motor 14. When it isdesired -to start an intermittent truing cycle, the start switch PB1 ismomentarily closed to energize the relay .switch CR1. The energizing ofrelay switch CR1 sets `up a holding circuit through the contacts 217'andt At the with the ratchet f v '10 to energize the solenoid S1 toshift the control valve toward the right so that uid under pressure fromthe pipe 103 passes through the valve chamber 108, through the pipe 76into the cylinder chamber 130 to start the piston 128 and the slide 123moving toward the right (Fig. 7). Fluid under pressure passes from thecylinder 130 through the passage 199, through the pipe 181 into thecylinder chamber V182 to cause a downward movement of the piston 176thereby causing the pawl 177 to ride idly over the teeth of the ratchetwheel 166. The valve member 196 moves rapidly to- Ward the right so thatfluid under pressure passes only momentarily through the pipe 181. Assoon as the valve member 196 reaches a right hand end position, thereleased compression of the spring 178 causes an upward movement of thepiston 176 and the pawl 177 thereby imparting a rotary motion to theratchet Wheel 166 which imparts a predetermined down feeding movement tothe truing tool 138 in a manner previously described. This feedingmovement takes place before the truing tool 138 moves into engagementwith the peripheral face of the grinding wheel 13. When the slide 123together with the truing tool 138 reach the right hand end of theirstroke, the slide 123 engages the actuating plunger of the limit switchLS1 and opens the contacts thereof thereby breaking the holding circuitto deenergize the relay switch CR1. The deenengizing relay switch CR1serves to deenergize the solenoid S1 so that the released compression ofthe spring 111 shifts the valve stem 106 toward the left into theposition illustrated in Fig. 7. In this position of the valve 105 iluidunder pressure entering the yvalve chamber 108 passes through the pipe96 into the cylinder chamber 131 to start the piston 128 together withthe slide 123 moving toward the left. At the same time fluid underpressure in the cylinder chamber 131 passes through the passage 203,through the valve chamber 198, through the pipe 191 into the cylinderchamber 192 to cause a downward movement of the piston 186 therebymoving the pawl 187 downwardly to impart a rotary motion to the ratchetwheel 166 which is transmitted to cause a predetermined down feedingmovement of the truing tool 138 before the truing tool moves in-toengagement with the operative face of the grinding wheel 13. Fluid underpressure is passed only momentarily through the pipe 191. 'Ihe valvemember 196 moves rapidly toward the left so that the releasedcompression of the spring 188 exhausts fluid from the cylinder chamber192, through the pipe 191, through the valve chamber 198 and through thepipe 201 into the reservoir 102. By manipulation of the stop screws and190, the extent of down feed of the truing tool 138 at each end of thetraversing stroke may be varied as desired.

When the truing apparatus is set for an intermittent truing operation,the valve 97 is opened and the valve 77 is closed so as to render theintermittent compensator piston 66 inoperative Iand to render thecontinuous truing compensator piston 86 operative: so that when thetruing tool 138 starts traversing toward the left, fluid under pressureis passed throu-gh the pipe 96 it passes through the pipe 98 into thecylinder chamber 93 to cause a downward movement of the piston 86. Thedownward movement of the piston 86 causes a downward movement of thepawl 87 to impart a rotary motion to the ratchet wheel 88 toautomatically impart a compensating adjustment to the wheel feedmechanism as previously described. The compensating mechanism is`arranged so that each tooth on the ratchet wheel 88 which is picked bythe downward movement of the pawl 87 gives a .0005 of an inchcompensating adjustment to the feed screw 20. A push button stop switchPB2 is provided to facili-tate stopping the truing cycle at any timedesired. When the apparatus is set for intermittent same time thecontacts 218 of the relay switch CR1 close 75 truing Operation thediamond or truing tool 138 makes 111 one complete reciprocation acrossthe operative face of the ,grinding wheel and then stops in the positionshown in .Figure 7.

When it is desired to Vprovide an automatic continuous truing of thegrinding wheel during a grinding operation, a manually operable switchSW1 may be closed. The switch SW1 is connected in series with a normallyopen limit switch LS2. The closing of the switch SW1 serves to energizethe relay switch CRI to start a traversing movement of a truing tool 138toward the right. When the apparatus is set vfor continuous truing, thevalve "7 is opened and the Valve 97 closed thereby rendering the feedcompensator 8S operative during a continuous truing operation. During acontinuous ltruing operation the piston `12S together with the slide 123reciprocates continuously so as to 'continuously reciprocate the truingtool 138 across the operative face of the grinding wheel 13. A 'finedown feeding movement of the diamond or truing tool 13S is obtained ateach end of the truing tool stroke, DuringV this operation, the knob 146'is moved upwardly so that the drive pin 168 engages the notch in the'worm gear 167. When 'fluid under pressure is passed through `th'e pipe181 at the start of a traversing movement of the truing tool 138 towardthe right, the piston 176 together with vthe pawl 214 moves downwardlyso that the pawl 214 imparts a rotary motion to the ratchet wheel 212which is transmitted through the worm 210 and the worm gear 167 toimpart a iine vdown feeding movement to the truing tool 138 before thetruing tool moves into engagement with the operative face of thegrinding wheel '13.

When the slide 123 approaches the end of its 'stroke 'toward the right,the limit switch LS1 is opened to 'deenergize the relay switch CR1thereby deenergizing "the `solenoid S1 so that the valve 195 shifts intothe posi- 'tion illustrated in Fig. 7. In this position, uid 'underpressure passes through the pipe 96 into the cylinder chamber 131 tostart the movement of the piston 122', and the slide 123 toward theleft. At this time uid -under pressure passes momentarily through thepipe 191 into the cylinder` chamber 192 to cause a downward movement ofthe piston 186 `so that the pawl 215 imparts l'an indexing movement tothe ratchet wheel 213. Rotary motion of the ratchet wheel 213 isimparted through the worm 21!) and the worm gear 167 to impart a finedown feeding movement to the truing tool 138 "before it moves intoengagement with the operative face of the grinding wheel on its stroketoward the left. The feed compensating mechanism is adjusted so that onecompensation is imparted to the feed screw during each completereciprocation of the truing tool when the truing tool 138 startstraversing toward the left.

As `the slide 123 approaches the left hand end of its stroke during acontinuous truing cycle, it closes the normally open limit. switch LS2'to again energize the re'lay switch CRI to start the next reciprocationof the `truing tool 138. yIt-will be readily apparent'from the foregoingdisclosure that each time the truing tool starts a traversing movement,a down feeding movement is .imparted to the truing tool 138 when theapparatus is :set up for either intermittent or continuous truing. Aspreviously stated Vonly one compensation is made to 'the .feedingmechanism for each complete reciprocation of the truing tool when thetruing apparatus is set up for either intermittent or continuousoperation.

When it is desired to stop a continuous truing cycle, the switch SW1 isopened thereby rendering the limit switch LS1 inoperative so that theslide 123 and truing tool 4138 will stop after one completereciprocation.

It will thus be seen that there has been provided by this invention agrinding wheel truing apparatus in which the various objects hereinaboveset forth together with many thoroughly practical advantages aresuccessfully achieved. As many possible embodiments may be made of theabove -invention and as many changes might be made in the embodimentabove set forth, it is to be understood that all matter hereinbefore setforth or shown in the -accompanying drawings is to be interpreted asillustrative and not in a limiting sense.

I claim:

l. In a grinding machine having a transversely movable wheel slide, aVrotatable grinding wheel thereon, a feeding mechanism to impart a'feeding movement to said slide in either direction, a grinding wheeltruing apparatus including a longitudinally traversable truing tool,means to reciprocate said truing tool either through one completereciprocation for an intermittent truing cycle or to reciprocate saidtruing tool continuously fora `continuous truing cycle, a truing toolfeed mechanism to feed said truing tool transversely, means actuated byand in timed 'relation with the longitudinal movement of the truing toolto actuate said truing tool feeding mechanism at each end of the 'truingtool traverse either at a line feed for a continuous truing cycle or ata coarser feed for an intermittent truing cycle, and a wheel 'feedcompensator mechanism actuated 'by and in timed relation with thelongitudinal traversing movement of the truing tool automatically toimpart a compensating adjustment to the wheel 'feeding mechanism eachtime the 'truing tool reciprocates, said feed compensation beingarranged so as to impart either a fine adjustment during a continuoustruing cycle or a coarser adjustment during an intermittent truingcycle.

2. In a grinding machine having a transversely movable `wheel slide, arotatable grinding Wheel thereon, means 'including a nut and screw feedmechanism operatively connected to feed said slide in either direction,a grinding wheel truing device including a longitudinally `traversabletruing tool slide, a transversely movable truing tool on said truingtool slide, `a piston and cylinder to traverse said truing tool slidelongitudinally, a truing tool feeding mechanism including a iiuidpressure 'actuated pawl and ratchet mechanism actuated by and in timedrelation with the ltraversing movement of said truing tool to feed saidtool either at a tine or at a coarse rate at each `end of the traversingmovement of the truing tool slide` and an independent iiuid pressureactuated pawl and ratchet mechanism actuated wheelfeed compensatoractuated in timed relation with the longitudinal traversing movement -ofthe truing tool slide automatically to impart a rotary motion to thefeed screw either at a tine or at a coarse rate during each truing cycleso as to compensate for reduction in diameter of the grinding wheel.

3. In a grinding machine, as claimed in claim 2 in lcombination with theparts and features therein specified of means including a rotatable nutand a feed screw to feed said truing tool, means including a ratchelwheel to impart a rotary mot-ion to said nut, a pair of independentfluid pressure actuated pawls to actuate said ratchet wheel at the startof the traversing movement of the `truing tool slide in either direction-to impart a feeding movement to said truingitool, and meansindependently to vary the extent of feed at each `end of the traversingmovement of the truing tool.

4. In a grinding machine, according to claim 2, in combination with theparts and features therein specified in which truing tool -feedingvmechanism includes a rotatable nut and a feed screw, means including aratchet wheel operatively connected to impart a rotary motion to saidnut to feed the truing tool during an intermittent truing cycle, meansincluding an independent ratchet wheel operatively connected to impart arelatively fine rotary motion to said nut at each end of the traversingmovement of the truing tool slide during a -continuous truing cycle, `apair of independent piston and cylinder actuated pawls to impart arotary motion to either ofthe .ratchet wheels at each lend of thetraversing movement of the truing tool slide, vand a clutch mechanism torender Vonly one of the ratchet wheels operative at a given time.

5. In a grinding machine as claimed in claim 2, in

combination with the parts and features therein specified in which saidWheel feed compensator includes a pawl and ratchet actuated slow speedgear mechanism operatively connected to impart a ne rotary motion tosaid feed screw during a continuous truing cycle, an independent pawland ratchet actuated faster speed gear mechanism operatively connectedto impart a coarser rotary motion to said feed screw during anintermittent truing cycle, an independent piston and cylinder to actuateeach of said pawl and ratchet mechanisms, an independent adjustable stopto limit the movement of said pistons to determine the extent of feedcompensation for each actuation, and an independent control valve torender either of said pistons inoperative.

6. In a grinding machine having a grinding wheel truing apparatusincluding a longitudinally traversable truing tool slide, a transverselymovable truing tool thereon, a nut and screw feeding mechanism to feedsaid tool relative to said slide, means actuated by and in timedrelation with the longitudinal movement of the truing tool to actuatethe nut and screw mechanism in one direction so as to unwind the feedmechanism, means to thereafter impart a predetermined incrementalfeeding movement to said feed mechanism and thereafter to actuate saidnut and screw mechanism in the opposite direction so as to wind saidfeed mechanism to position the truing tool for a traversing movementacross the operative face of the grinding wheel.

7. In a grinding machine having a grinding Wheel truing apparatusincluding a longitudinally traversable truing tool slide, a transverselymovable truing tool thereon, means including a rotatable nut and screwto feed said tool transversely, means actuated by and in timed relationwith the longitudinal movement of the truing tool to actuate said feednut in one direction so as to unwind said feed nut, means to thereafterimpart a predetermined incremental rotary feeding movement to said feednut and means thereafter tot actuate said feed nut in the otherdirection so as to impart a rotary wind movement of said feed nut toposition the truing tool for a traversing movement across the operativeface of the grinding wheel.

8. In a grinding machine having a grinding Wheel truing apparatusincluding a longitudinally traversable truing tool slide, a transverselymovable truing tool on said slide, means to traverse said slidelongitudinally to traverse fthe truing tool across the operative face ofa grinding wheel, a nut and screw feed mechanism to feed said truingtool transversely, means including adjustable dogs actuated by and intimed relation With the longitudinal movement of the truing tool slideto actuate said feed nut in one direction so as to unwind the feed nut,means to thereafter impart a predetermined incremental rotary feedingmovement to said feed nut, and yieldable means thereafter to actuatesaid feed nut in the opposite direction so as to impart a rotary wind tosaid feed nut to position the truing tool for a traversing movementacross the operative face of the grinding wheel.

References Cited in the tile of this patent UNITED STATES PATENTS2,597,242 Hill May 20, 1952 2,647,504 Hill Aug. 4, 1953 2,720,063 HillOct. 11, 1955

